8.3 High
CVSS3
Attack Vector
ADJACENT
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
CHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H
8.5 High
AI Score
Confidence
Low
0.025 Low
EPSS
Percentile
90.3%
The remote CentOS Linux 7 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2024:1959 advisory.
A flaw was found in Shim when an error happened while creating a new ESL variable. If Shim fails to create the new variable, it tries to print an error message to the user; however, the number of parameters used by the logging function doesn’t match the format string used by it, leading to a crash under certain circumstances. (CVE-2023-40546)
A remote code execution vulnerability was found in Shim. The Shim boot support trusts attacker-controlled values when parsing an HTTP response. This flaw allows an attacker to craft a specific malicious HTTP request, leading to a completely controlled out-of-bounds write primitive and complete system compromise.
This flaw is only exploitable during the early boot phase, an attacker needs to perform a Man-in-the- Middle or compromise the boot server to be able to exploit this vulnerability successfully.
(CVE-2023-40547)
A buffer overflow was found in Shim in the 32-bit system. The overflow happens due to an addition operation involving a user-controlled value parsed from the PE binary being used by Shim. This value is further used for memory allocation operations, leading to a heap-based buffer overflow. This flaw causes memory corruption and can lead to a crash or data integrity issues during the boot phase. (CVE-2023-40548)
An out-of-bounds read flaw was found in Shim due to the lack of proper boundary verification during the load of a PE binary. This flaw allows an attacker to load a crafted PE binary, triggering the issue and crashing Shim, resulting in a denial of service. (CVE-2023-40549)
An out-of-bounds read flaw was found in Shim when it tried to validate the SBAT information. This issue may expose sensitive data during the system’s boot phase. (CVE-2023-40550)
A flaw was found in the MZ binary format in Shim. An out-of-bounds read may occur, leading to a crash or possible exposure of sensitive data during the system’s boot phase. (CVE-2023-40551)
Note that Nessus has not tested for these issues but has instead relied only on the application’s self-reported version number.
#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Red Hat Security Advisory RHSA-2024:1959.
##
include('compat.inc');
if (description)
{
script_id(193955);
script_version("1.0");
script_set_attribute(attribute:"plugin_modification_date", value:"2024/04/26");
script_cve_id(
"CVE-2023-40546",
"CVE-2023-40547",
"CVE-2023-40548",
"CVE-2023-40549",
"CVE-2023-40550",
"CVE-2023-40551"
);
script_xref(name:"RHSA", value:"2024:1959");
script_name(english:"CentOS 7 : shim (RHSA-2024:1959)");
script_set_attribute(attribute:"synopsis", value:
"The remote CentOS Linux host is missing one or more security updates.");
script_set_attribute(attribute:"description", value:
"The remote CentOS Linux 7 host has packages installed that are affected by multiple vulnerabilities as referenced in the
RHSA-2024:1959 advisory.
- A flaw was found in Shim when an error happened while creating a new ESL variable. If Shim fails to create
the new variable, it tries to print an error message to the user; however, the number of parameters used
by the logging function doesn't match the format string used by it, leading to a crash under certain
circumstances. (CVE-2023-40546)
- A remote code execution vulnerability was found in Shim. The Shim boot support trusts attacker-controlled
values when parsing an HTTP response. This flaw allows an attacker to craft a specific malicious HTTP
request, leading to a completely controlled out-of-bounds write primitive and complete system compromise.
This flaw is only exploitable during the early boot phase, an attacker needs to perform a Man-in-the-
Middle or compromise the boot server to be able to exploit this vulnerability successfully.
(CVE-2023-40547)
- A buffer overflow was found in Shim in the 32-bit system. The overflow happens due to an addition
operation involving a user-controlled value parsed from the PE binary being used by Shim. This value is
further used for memory allocation operations, leading to a heap-based buffer overflow. This flaw causes
memory corruption and can lead to a crash or data integrity issues during the boot phase. (CVE-2023-40548)
- An out-of-bounds read flaw was found in Shim due to the lack of proper boundary verification during the
load of a PE binary. This flaw allows an attacker to load a crafted PE binary, triggering the issue and
crashing Shim, resulting in a denial of service. (CVE-2023-40549)
- An out-of-bounds read flaw was found in Shim when it tried to validate the SBAT information. This issue
may expose sensitive data during the system's boot phase. (CVE-2023-40550)
- A flaw was found in the MZ binary format in Shim. An out-of-bounds read may occur, leading to a crash or
possible exposure of sensitive data during the system's boot phase. (CVE-2023-40551)
Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version
number.");
script_set_attribute(attribute:"see_also", value:"https://access.redhat.com/errata/RHSA-2024:1959");
script_set_attribute(attribute:"solution", value:
"Update the affected packages.");
script_set_cvss_base_vector("CVSS2#AV:A/AC:H/Au:N/C:C/I:C/A:C");
script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
script_set_cvss3_base_vector("CVSS:3.0/AV:A/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H");
script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
script_set_attribute(attribute:"cvss_score_source", value:"CVE-2023-40547");
script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
script_set_attribute(attribute:"exploit_available", value:"false");
script_set_attribute(attribute:"vendor_severity", value:"Important");
script_set_attribute(attribute:"vuln_publication_date", value:"2023/12/11");
script_set_attribute(attribute:"patch_publication_date", value:"2024/04/23");
script_set_attribute(attribute:"plugin_publication_date", value:"2024/04/26");
script_set_attribute(attribute:"plugin_type", value:"local");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:mokutil");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:shim-ia32");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:shim-unsigned-ia32");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:shim-unsigned-x64");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:shim-x64");
script_set_attribute(attribute:"cpe", value:"cpe:/o:centos:centos:7");
script_set_attribute(attribute:"generated_plugin", value:"current");
script_end_attributes();
script_category(ACT_GATHER_INFO);
script_family(english:"CentOS Local Security Checks");
script_copyright(english:"This script is Copyright (C) 2024 and is owned by Tenable, Inc. or an Affiliate thereof.");
script_dependencies("ssh_get_info.nasl");
script_require_keys("Host/local_checks_enabled", "Host/CentOS/release", "Host/CentOS/rpm-list", "Host/cpu");
exit(0);
}
include('rpm.inc');
include('rhel.inc');
if (!get_kb_item('Host/local_checks_enabled')) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
var os_release = get_kb_item('Host/CentOS/release');
if (isnull(os_release) || 'CentOS' >!< os_release) audit(AUDIT_OS_NOT, 'CentOS');
var os_ver = pregmatch(pattern: "CentOS(?: Linux)? release ([0-9]+)", string:os_release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, 'CentOS');
os_ver = os_ver[1];
if (!rhel_check_release(operator: 'ge', os_version: os_ver, rhel_version: '7')) audit(AUDIT_OS_NOT, 'CentOS 7.x', 'CentOS ' + os_ver);
if (!get_kb_item('Host/CentOS/rpm-list')) audit(AUDIT_PACKAGE_LIST_MISSING);
var cpu = get_kb_item('Host/cpu');
if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH);
if ('x86_64' >!< cpu && cpu !~ "^i[3-6]86$" && 's390' >!< cpu && 'aarch64' >!< cpu && 'ppc' >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'CentOS', cpu);
var pkgs = [
{'reference':'mokutil-15.8-1.el7', 'cpu':'x86_64', 'release':'CentOS-7', 'rpm_spec_vers_cmp':TRUE},
{'reference':'shim-ia32-15.8-1.el7', 'cpu':'x86_64', 'release':'CentOS-7', 'rpm_spec_vers_cmp':TRUE},
{'reference':'shim-unsigned-ia32-15.8-3.el7', 'cpu':'x86_64', 'release':'CentOS-7', 'rpm_spec_vers_cmp':TRUE},
{'reference':'shim-unsigned-x64-15.8-3.el7', 'cpu':'x86_64', 'release':'CentOS-7', 'rpm_spec_vers_cmp':TRUE},
{'reference':'shim-x64-15.8-1.el7', 'cpu':'x86_64', 'release':'CentOS-7', 'rpm_spec_vers_cmp':TRUE}
];
var flag = 0;
foreach var package_array ( pkgs ) {
var reference = NULL;
var _release = NULL;
var sp = NULL;
var _cpu = NULL;
var el_string = NULL;
var rpm_spec_vers_cmp = NULL;
var epoch = NULL;
var allowmaj = NULL;
if (!empty_or_null(package_array['reference'])) reference = package_array['reference'];
if (!empty_or_null(package_array['release'])) _release = package_array['release'];
if (!empty_or_null(package_array['sp'])) sp = package_array['sp'];
if (!empty_or_null(package_array['cpu'])) _cpu = package_array['cpu'];
if (!empty_or_null(package_array['el_string'])) el_string = package_array['el_string'];
if (!empty_or_null(package_array['rpm_spec_vers_cmp'])) rpm_spec_vers_cmp = package_array['rpm_spec_vers_cmp'];
if (!empty_or_null(package_array['epoch'])) epoch = package_array['epoch'];
if (!empty_or_null(package_array['allowmaj'])) allowmaj = package_array['allowmaj'];
if (reference && _release) {
if (rpm_check(release:_release, sp:sp, cpu:_cpu, reference:reference, epoch:epoch, el_string:el_string, rpm_spec_vers_cmp:rpm_spec_vers_cmp, allowmaj:allowmaj)) flag++;
}
}
if (flag)
{
security_report_v4(
port : 0,
severity : SECURITY_WARNING,
extra : rpm_report_get()
);
exit(0);
}
else
{
var tested = pkg_tests_get();
if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
else audit(AUDIT_PACKAGE_NOT_INSTALLED, 'mokutil / shim-ia32 / shim-unsigned-ia32 / etc');
}
Vendor | Product | Version | CPE |
---|---|---|---|
centos | centos | mokutil | p-cpe:/a:centos:centos:mokutil |
centos | centos | shim-ia32 | p-cpe:/a:centos:centos:shim-ia32 |
centos | centos | shim-unsigned-ia32 | p-cpe:/a:centos:centos:shim-unsigned-ia32 |
centos | centos | shim-unsigned-x64 | p-cpe:/a:centos:centos:shim-unsigned-x64 |
centos | centos | shim-x64 | p-cpe:/a:centos:centos:shim-x64 |
centos | centos | 7 | cpe:/o:centos:centos:7 |
cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-40546
cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-40547
cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-40548
cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-40549
cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-40550
cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-40551
access.redhat.com/errata/RHSA-2024:1959
8.3 High
CVSS3
Attack Vector
ADJACENT
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
CHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H
8.5 High
AI Score
Confidence
Low
0.025 Low
EPSS
Percentile
90.3%